The star, wife of TV producer Steve Stark, died last Thursday (04Nov10) in Los Angeles, according to the Hollywood Reporter.
Nicastro launched her screen career in 1983 and landed a small role in Billy Crystal and Meg Ryan's 1989 romantic comedy When Harry Met Sally...
She also appeared in TV hits Beverly Hills, 90210, Knight Rider and Full House, and voiced the character of Princess Odette in The Swan Princess and its subsequent sequels.
Nicastro showed off her vocal talents during a stint on Broadway in a 1983 production of the musical Merlin, and toured the U.S. as a castmember of Les Miserables in 1988.
She also released four albums as a singer and performed alongside Barry Manilow on his international Showstoppers Tour.
Nicastro is survived by her husband of 24 years, their daughters Callie and Cady and sisters Beth Ann and Kristin.